Damage control: fall period critical to rebuilding lawn

Unfortunately, we are ending an unusually dry summer with and unusually dry fall.

The lack of rain has made it difficult to overseed and fertilize cool season lawns. Nevertheless, it is time to start helping what is left of the lawns recover. Cool weather and timely rains are the stimulus for new growth in bluegrass and fescue lawns.

The fall growth period is important because grass can repair summer damage and accumulate food reserves crucial for winter survival. Unfortunately, the fall growth cannot happen without adequate amounts of soil moisture and nutrients.

With this in mind, now is the time to turn on the sprinkler and begin applying turfgrass fertilizers. Here are a few tips to help you spread the nutrients to achieve the most out of your cool season lawn.

September and November are two of the best months to apply lawn fertilizers. The cool weather and timely rains help activate fertilizers and stimulate growth. To supplement the rain this year, begin to apply the recommended one inch of water as needed especially if you have overseeded.

Next, apply fertilizer. Nitrogen is especially important this time of year because it helps grass produce new leaves. Only with new leaf tissue can the plants manufacture the energy necessary for crown building, root development, and food storage. The stronger and healthier the grass is this fall, the greater chances of survival this winter.

When fertilizing your lawn, use a fertilizer designed for turf grass. Turf grass fertilizers contain a greater amount of nitrogen in relation to phosphorus and potassium. The percent nitrogen is the first number of the three number analysis on a bag of fertilizer. Phosphorus and potassium are the other two nutrients reported respectively.

To determine how much fertilize you should apply, divide 100 by the first number or the percent nitrogen in the bag. The answer you get is how many pounds of the fertilizer you should apply to 1,000-square feet of lawn.

Thoroughly irrigate the lawn if rain is not expected. Do not subscribe to the theory that if a little is good, a lot must be better. Applying excess fertilizers wastes money and can pollute surface and ground water.

Finally, mow the grass high. Research has found that the higher the grass is mowed, the deeper the root system will grow. This means a tougher, more healthy stand of grass. For best results, mow the lawn at least two to years inches tall. Mow regularly and only remove one-third of the grass blades off. This may mean mowing every four or five days this time of year.


Bruce Chladny is horticulture agent at K-State Research and Extension-Douglas County. For more information, call him at 843-7058 from 8 a.m. to 5 p.m. weekdays.